
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TRBL
SHTG
EAS00845
TROUBLESHOOTING
NOTE:
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The following guide for troubleshooting does not cover all the possible causes of trouble. It should
be helpful, however, as a guide to basic troubleshooting. Refer to the relative procedure in this man-
ual for checks, adjustments, and replacement of parts.
STARTING FAILURE/HARD STARTING
ENGINE
Cylinder and cylinder head
• Loose spark plug
• Loose cylinder head or cylinder
• Damaged cylinder head gasket
• Damaged cylinder gasket
• Worn or damaged cylinder
• Incorrect valve clearance
• Improperly sealed valve
• Incorrect valve-to-valve-seat contact
• Incorrect valve timing
• Faulty valve spring
• Seized valve
Piston and piston ring(s)
• Improperly installed piston ring
• Damaged, worn or fatigued piston ring
• Seized piston ring
• Seized or damaged piston
Air filter
• Improperly installed air filter
• Clogged air filter element
Crankcase and crankshaft
• Improperly assembled crankcase
• Seized crankshaft
FUEL SYSTEM
Fuel tank
• Empty fuel tank
• Clogged fuel tank cap breather hole
• Deteriorated or contaminated fuel
• Clogged or damaged fuel hose
Fuel pump
• Faulty fuel pump
• Faulty fuel injection system relay
• Improperly routed hose
Throttle body
• Deteriorated or contaminated fuel
• Sucked-in air
STARTING FAILURE/HARD STARTING
Summary of Contents for 2004 YP400
Page 1: ...2004 YP400 S 5RU1 AE1 SERVICE MANUAL ...
Page 2: ......
Page 8: ......
Page 9: ...GEN INFO 1 ...
Page 11: ...GEN INFO ...
Page 28: ...SPEC 2 ...
Page 30: ...SPEC ...
Page 77: ...CHK ADJ 3 ...
Page 137: ......
Page 138: ...CHAS 4 ...
Page 210: ......
Page 211: ...ENG 5 ...
Page 286: ...COOL 6 ...
Page 288: ...COOL ...
Page 299: ...FI 7 ...
Page 301: ...FI ...
Page 342: ...ELEC 8 ...
Page 378: ...8 34 ELEC LIGHTING SYSTEM ...
Page 404: ......
Page 405: ...TRBL SHTG 9 ...
Page 415: ......
Page 416: ...YAMAHA MOTOR CO LTD 2500 SHINGAI IWATA SHIZUOKA JAPAN ...